Multi-omics analysis reveal the fall armyworm Spodoptera frugiperda tolerate high temperature by mediating chitin-related genes.

Climate change facilitates the rapid invasion of agricultural pests, threatening global food security. The fall armyworm Spodoptera frugiperda is a highly polyphagous migratory pest tolerant to high temperatures, allowing its proliferation in harsh thermal environments. We aimed to demonstrate mechanisms of its high-temperature tolerance, particularly transcriptional and metabolic regulation, which are poorly understood. To achieve the aim, we examined the impact and mechanism of heat events on S. frugiperda by using multiple approaches: ecological measurements, transcriptomics, metabolomics, RNAi, and CRISPR/Cas9 technology. We observed that several physiological indices (larval survival rate, larval period, pupation rate, pupal weight, eclosion rate, and average fecundity) decreased as the temperature increased, with the 32 °C treatment displaying a significant difference from the control group at 26 °C. Significantly upregulated expression of genes encoding endochitinase and chitin deacetylase was observed in the chitin-binding, extracellular region, and carbohydrate metabolic process GO terms of hemolymph, fat body, and brain, exhibiting a tissue-specific pattern. Significantly enriched pathways (e.g., cutin, suberin, and wax biosynthesis; oxidative phosphorylation and cofactor biosynthesis; diverse amino acid biosynthesis and degradation; carbon metabolism; and energy metabolism), all of which are essential for S. frugiperda larvae to tolerate temperature, were found in metabolites that were expressed differently. Successful RNA interference targeting of the three chitin-related genes reduced gene expression levels and larval survival rate. Knockout of the endochitinase gene by using the CRISPR/Cas9 system significantly reduced the relative gene expression and increased sensitivity to high-temperature exposure. On the basis of our findings, theoretical foundations for understanding the high-temperature tolerance of S. frugiperda populations and latent genetic control strategies were established.

The water-exiting behavior and survival of predaceous diving beetles in responses to lambda-cyhalothrin, chlorantraniliprole, and thiamethoxam.

Predaceous diving beetles (dytiscids) are important top insect predators in various natural, agricultural, and artificial water bodies. How they respond to human disturbances such as insecticide contamination to their habitats has been understudied. In this study, we investigated the lethal effects of lambda-cyhalothrin, chlorantraniliprole, and thiamethoxam at nominal field concentrations in 3 cm-deep water in a hypothetical paddy field (Ci,3) on adult Dytiscus sinensis Feng (Coleoptera: Dytiscidae). Lambda-cyhalothrin exhibited significant lethal effects on D. sinensis adults with its Ci,3 exceeding the 95 % confidence interval lower limits for 24, 48, 72, and 96 h- LC99. Chlorantraniliprole and thiamethoxam showed no significant lethal effects on D. sinensis adults at their respective Ci,3 at 24, 48, or 72 h. Additionally, we assessed the temporal propensity of D. sinensis adults to exit water contaminated with chlorantraniliprole and thiamethoxam, respectively. There were significantly more individuals that temporally exited the chlorantraniliprole-contaminated water than clean water 30 min after placing a tile island in the test arena. Meanwhile, thiamethoxam-contaminated water did not repel significantly more individuals than clean water when observed at 10, 30, or 60 min. The study highlights the availability and importance of selecting safer insecticides for dytiscid conservation in agricultural and adjacent habitats, considering the potential of these water bodies becoming ecological traps that keep attracting and killing aquatic beneficials. The water-exiting behavior found indicates the capability of some wildlife to effectively avoid further exposure to toxicants.

LmFKBP24 interacts with LmEaster to inhibit the antifungal immunity of Locusta migratoria.

Locusta migratoria is one of the most destructive pests that threaten crop growth and food production security in China. Metarhizium anisopliae has been widely used to control locusts around the world. Previous laboratory studies have revealed that LmFKBP24 is significantly upregulated after M. anisopliae infection, suggesting that it may play a role in immune regulation, yet the mechanism remains largely unknown. To gain further insight, we conducted an RNA interference (RNAi) study to investigate the function of LmFKBP24 in the regulation of antifungal immunity and analyzed the expression patterns of immune-induced genes. Our research revealed that LmFKBP24 is activated and upregulated when locusts are infected by M. anisopliae, and it inhibits the expression of antimicrobial peptide (AMP) defensin in the downstream of Toll pathway by combining with LmEaster rather than LmCyPA, thus exerting an immunosuppressive effect. To further investigate this, we conducted yeast two-hybrid (Y2H) and pull down assays to identify the proteins interacting with LmFKBP24. Our results provided compelling evidence for revealing the immune mechanism of L. migratoria and uncovered an innovative target for the development of new biological pesticides. Furthermore, our research indicates that LmFKBP24 interacts with LmEaster through its intact structure, providing a strong foundation for further exploration.

An advanced approach for rapid visual identification of Liposcelis bostrychophila (Psocoptera: Liposcelididae) based on CRISPR/Cas12a combined with RPA.

Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae) is a booklouse pest that is a threat to commodity storage security worldwide. Accurate and sensitive methods of L. bostrychophila on-site identification are essential prerequisites for its effective management. Evidence suggests that L. bostrychophila contains 3 intraspecific biotypes that are morphologically indistinguishable but can be discriminated at the level of mitochondrial genome organization and sequences. The traditional molecular identification methods, such as DNA barcoding and PCR-RFLP, are instrumentally demanding and time-consuming, limiting the application of the identification in the field. Therefore, this study developed a new CRISPR/Cas12a-based visual nucleic acid system based on the mitochondrial gene coding for NADH dehydrogenase subunit 2 (nad2), combined with recombinase polymerase amplification (RPA) to accurately identify L. bostrychophila from 4 other common stored-product booklice, and also differentiate 3 biotypes of this species at the same time. The entire identification process could be completed at 37 °C within 20 min with high sensitivity. The system could stably detect at least 1 ng/µl of DNA template. The green fluorescence signal produced by the trans-cleaving of the single-stranded DNA reporter could be observed by the naked eye under blue light. Additionally, the suggested system combined with the crude DNA extraction method to extract DNA rapidly, enabled identification of all developmental stages of L. bostrychophila. With crude DNA, this novel diagnostic system successfully identified an unknown booklouse by holding the reaction tubes in the hand, thus can be considered as an accurate, rapid, highly sensitive, and instrument-flexible method for on-site visual identification of L. bostrychophila.

Identification, characterization and spatiotemporal expression analysis of the FKBP family genes in Locusta migratoria.

FK506 binding proteins (FKBPs) are a highly-conserved group of proteins known to bind to FK506, an immunosuppressive drug. They play different physiological roles, including transcription regulation, protein folding, signal transduction and immunosuppression. A number of FKBP genes have been identified in eukaryotes; however, very little information about these genes has been reported in Locusta migratoria. Here, we identified and characterized 10 FKBP genes from L. migratoria. Phylogenetic analysis and comparison of domain architectures indicated that the LmFKBP family can be divided into two subfamilies and five subclasses. Developmental and tissue expression pattern analysis revealed that all LmFKBPs transcripts, including LmFKBP46, LmFKBP12, LmFKBP47, LmFKBP79, LmFKBP16, LmFKBP24, LmFKBP44b, LmFKBP53, were periodically expressed during different developmental stages and mainly expressed in the fat body, hemolymph, testis, and ovary. In brief, our work depicts a outline but panoramic picture of LmFKBP family in L. migratoria, and provides a solid foundation to further investigate the molecular functions of LmFKBPs.

Genomes of the cosmopolitan fruit pest Bactrocera dorsalis (Diptera: Tephritidae) reveal its global invasion history and thermal adaptation.

INTRODUCTION: The oriental fruit fly Bactrocera dorsalis is one of the most destructive agricultural pests worldwide, with highly debated species delimitation, origin, and global spread routes. OBJECTIVES: Our study intended to (i) resolve the taxonomic uncertainties between B. dorsalis and B. carambolae, (ii) reveal the population structure and global invasion routes of B. dorsalis across Asia, Africa, and Oceania, and (iii) identify genomic regions that are responsible for the thermal adaptation of B. dorsalis. METHODS: Based on a high-quality chromosome-level reference genome assembly, we explored the population relationship using a genome-scale single nucleotide polymorphism dataset generated from the resequencing data of 487 B. dorsalis genomes and 25 B. carambolae genomes. Genome-wide association studies and silencing using RNA interference were used to identify and verify the candidate genes associated with extreme thermal stress. RESULTS: We showed that B. dorsalis originates from the Southern India region with three independent invasion and spread routes worldwide: (i) from Northern India to Northern Southeast Asia, then to Southern Southeast Asia; (ii) from Northern India to Northern Southeast Asian, then to China and Hawaii; and (iii) from Southern India toward the African mainland, then to Madagascar, which is mainly facilitated by human activities including trade and immigration. Twenty-seven genes were identified by a genome-wide association study to be associated with 11 temperature bioclimatic variables. The Cyp6a9 gene may enhance the thermal adaptation of B. dorsalis and thus boost its invasion, which tended to be upregulated at a hardening temperature of 38 °C. Functional verification using RNA interference silencing against Cyp6a9, led to the specific decrease in Cyp6a9 expression, reducing the survival rate of dsRNA-feeding larvae exposed to extreme thermal stress of 45 °C after heat hardening treatments in B. dorsalis. CONCLUSION: This study provides insights into the evolutionary history and genetic basis of temperature adaptation in B. dorsalis.

Chromosome-level genome assembly of Bactrocera correcta provides insights into its adaptation and invasion mechanisms.

Bactrocera correcta is an invasive polyphagous pest with significant ecological and economic implications. Understanding its genetic characteristics and the molecular mechanisms that drive its rapid adaptation to new environments requires genomic information. In this study, we successfully assembled the chromosome-level genome of B. correcta using PacBio long-read sequencing, Illumina sequencing, and chromatin conformation capture (Hi-C) methods. The final genome assembly spans a total length of 702.65 Mb. We managed to anchor approximately 86.88% of the assembled contigs into 6 linkage groups, ranging from 17.97 Mb to 166.49 Mb. Additionally, our analysis predicted a total of 21,015 genes, with repetitive sequences accounting for 58.22% of the genome. We further identified retroelements and DNA transposons as the major contributors to the larger size of the B. correcta genome, constituting 36.06% and 30.92% of the repetitive sequences, respectively. Our divergence time estimation placed B. correcta's split from other Bactrocera species at around 5.99-16.71 million years ago. Through gene family analyses, we discovered significant expansions in sensing-related gene families (IR, GR), heat shock proteins (HSP60), and resistance-related gene families (ABC) in B. correcta compared to its closest relatives. Transcriptomic analysis revealed substantial upregulation of HSP genes, especially those from the HSP20 subfamily, in response to high temperatures. The availability of this reference genome serves as a foundation for the identification of precise target genes in B. correcta, facilitating molecular prevention and control strategies.

Impact of Temperature Change on the Fall Armyworm, Spodoptera frugiperda under Global Climate Change.

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith, 1797), known as an important agricultural pest around the world, is indigenous to the tropical-subtropical regions in the Western Hemisphere, although its distribution has expanded over large parts of America, Africa, Asia and Oceania in the last few years. The pest causes considerable costs annually coupled with its strong invasion propensity. Temperature is identified as the dominant abiotic factor affecting herbivorous insects. Several efforts have reported that temperature directly or indirectly influences the geographic distribution, phenology and natural enemies of the poikilothermal FAW, and thus may affect the damage to crops, e.g., the increased developmental rate accelerates the intake of crops at higher temperatures. Under some extreme temperatures, the FAW is likely to regulate various genes expression in response to environmental changes, which causes a wider viability and possibility of invasion threat. Therefore, this paper seeks to review and critically consider the variations of developmental indicators, the relationships between the FAW and its natural enemies and the temperature tolerance throughout its developmental stage at varying levels of heat/cold stress. Based on this, we discuss more environmentally friendly and economical control measures, we put forward future challenges facing climate change, we further offer statistical basics and instrumental guidance significance for informing FAW pest forecasting, risk analyses and a comprehensive management program for effective control globally.

A chromosome-level genome of the booklouse, Liposcelis brunnea, provides insight into louse evolution and environmental stress adaptation.

BACKGROUND: Booklice (psocids) in the genus Liposcelis (Psocoptera: Liposcelididae) are a group of important storage pests, found in libraries, grain storages, and food-processing facilities. Booklice are able to survive under heat treatment and typically possess high resistance to common fumigant insecticides, hence posing a threat to storage security worldwide. RESULTS: We assembled the genome of the booklouse, L. brunnea, the first genome reported in Psocoptera, using PacBio long-read sequencing, Illumina sequencing, and chromatin conformation capture (Hi-C) methods. After assembly, polishing, haplotype purging, and Hi-C scaffolding, we obtained 9 linkage groups (174.1 Mb in total) ranging from 12.1 Mb to 27.6 Mb (N50: 19.7 Mb), with the BUSCO completeness at 98.9%. In total, 15,543 genes were predicted by the Maker pipeline. Gene family analyses indicated the sensing-related gene families (OBP and OR) and the resistance-related gene families (ABC, EST, GST, UGT, and P450) expanded significantly in L. brunnea compared with those of their closest relatives (2 parasitic lice). Based on transcriptomic analysis, we found that the CYP4 subfamily from the P450 gene family functioned during phosphine fumigation; HSP genes, particularly those from the HSP70 subfamily, were upregulated significantly under high temperatures. CONCLUSIONS: We present a chromosome-level genome assembly of L. brunnea, the first genome reported for the order Psocoptera. Our analyses provide new insights into the gene family evolution of the louse clade and the transcriptomic responses of booklice to environmental stresses.

Fragmentation in mitochondrial genomes in relation to elevated sequence divergence and extreme rearrangements.

BACKGROUND: A single circular mitochondrial (mt) genome is a common feature across most metazoans. The mt-genome includes protein-coding genes involved in oxidative phosphorylation, as well as RNAs necessary for translation of mt-RNAs, whose order and number are highly conserved across animal clades, with few known exceptions of alternative mt-gene order or mt-genome architectures. One such exception consists of the fragmented mitochondrial genome, a type of genome architecture where mt-genes are split across two or more mt-chromosomes. However, the origins of mt-genome fragmentation and its effects on mt-genome evolution are unknown. Here, we investigate these origin and potential mechanisms underlying mt-genome fragmentation, focusing on a genus of booklice, Liposcelis, which exhibits elevated sequence divergence, frequent rearrangement of mt-gene order, and fragmentation of the mt genome, and compare them to other Metazoan clades. RESULTS: We found this genus Liposcelis exhibits very low conservation of mt-gene order across species, relative to other metazoans. Levels of gene order rearrangement were, however, unrelated to whether or not mt-genomes were fragmented or intact, suggesting mitochondrial genome fragmentation is not affecting mt-gene order directly. We further investigated possible mechanisms underpinning these patterns and revealed very high conservation of non-coding sequences at the edges of multiple recombination regions across populations of one particular Liposcelis species, supportive of a hypothesis that mt-fragmentation arises from recombination errors between mt-genome copies. We propose these errors may arise as a consequence of a heightened mutation rate in clades exhibiting mt-fragmentation. Consistent with this, we observed a striking pattern across three Metazoan phyla (Arthropoda, Nematoda, Cnidaria) characterised by members exhibiting high levels of mt-gene order rearrangement and cases of mt-fragmentation, whereby the mt-genomes of species more closely related to species with fragmented mt-genomes diverge more rapidly despite experiencing strong purifying selection. CONCLUSIONS: We showed that contrary to expectations, mt-genome fragmentation is not correlated with the increase in mt-genome rearrangements. Furthermore, we present evidence that fragmentation of the mt-genome may be part of a general relaxation of a natural selection on the mt-genome, thus providing new insights into the origins of mt-genome fragmentation and evolution.

Phylogenomic resolution of the Ceratitis FARQ complex (Diptera: Tephritidae).

The Ceratitis FARQ complex (formerly FAR complex) includes four frugivorous tephritids, Ceratitis fasciventris, C. anonae, C. rosa and C. quilicii, the latter two causing important agricultural losses in Africa. Although FARQ species can be identified on the basis of subtle morphological differences, they cannot be resolved as monophyletic when trying phylogenetic tree reconstructions based on mitochondrial or nuclear gene fragments except for microsatellites. In this study, we used mitogenome and genome-wide SNPs to investigate the phylogenetic relationship within the complex as well as between all four Ceratitis subgenera. The analysis of 13 species supported the monophyly of the Ceratitis subgenera Ceratitis, Ceratalaspis, Pardalaspis, and recovered Pterandrus as paraphyletic but could not properly resolve species within the FARQ complex. Conversely, gene and species tree reconstructions based on 785,484 genome-wide SNPs could consistently resolve the FARQ taxa and provide insights into their phylogenetic relationships. Gene flow was detected by TreeMix analysis from C. quilicii to C. fasciventris, suggesting the existence of introgression events in the FARQ complex. Our results suggest that genome-wide SNPs represent a suitable tool for the molecular diagnosis of FARQ species and could possibly be used to develop rapid diagnostic methods or to trace the origins of intercepted samples.

Comparative mitochondrial genomics of five Dermestid beetles (Coleoptera: Dermestidae) and its implications for phylogeny.

Dermestid beetles (Coleoptera: Dermestidae) are important pests of various stored products, posing potential threats to international trade. Their detailed characterization on molecular basis is a pre-requisite for proper identification and for understanding of their phylogenetic relationships. In this work, the whole mitochondrial genomes (mitogenomes) of Trogoderma granarium, Dermestes lardarius, D. ater, Attagenus augustatus augustatus and Attagenus unicolor japonicus were firstly sequenced to update the database using the next-generation sequencing technique. Based on the selected model species, a comparative analysis of four Dermestidae genera was performed. The mitochondrial genomes of these five species above showed high similarity in nucleotide composition, base composition and gene order, including 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs) and a non-coding control region, which was similar to most of Coleoptera species. The phylogenetic analysis based on the PCGs and two rRNAs indicated that the relationships within Dermestidae were reconstructed as (((Trogoderma + Anthrenus) + Attagenus) + Dermestes) using both Maximum Likelihood (ML) and Bayesian Inference (BI) analysis. However, more mitogenomes should be sequenced to obtain a more holistic view of the whole family. This study not only showed the mitogenomes of five Dermestidae species and their high conservativeness, but also discussed its implications for reconstructing a more comprehensive phylogeny of dermestids.

The first two complete mitochondrial genome of Dacus bivittatus and Dacus ciliatus (Diptera: Tephritidae) by next-generation sequencing and implications for the higher phylogeny of Tephritidae.

Dacus bivittatus and Dacus ciliatus are destructive pests of Cucurbitaceae crops including cucumber, zucchini and melons. Recent molecular phylogenetic studies conflicted with morphological taxonomy regarding relationships between Bactrocera, Dacus and Zeugodacus. In this study, we sequenced the complete mitochondrial genomes of the above species which are representatives of two subgenera of Dacus (Dacus and Didacus) not previously sequenced and reconstructed the phylogeny of Tephritidae. The mitochondrial genomes of D. bivittatus and D. ciliatus were 15,833 bp and 15,808 bp in length, respectively. The 37 genes, including 13 protein-coding genes (PCGs), 2 rRNA genes and 22 tRNA genes, with a long non-coding region (A + T-rich control region) were in the same arrangement as the ancestral insect mitochondrial genome. Phylogenetic analysis showed that Dacus has a closer relationship of Zeugodacus rather than Bactrocera. Our phylogenetic results further support the recent proposals that Zeugodacus should be considered as a genus not a subgenus of Bactrocera. Whole mitochondrial genomes of D. bivittatus and D. ciliatus could be useful in further studies for species diagnosis, evolution and phylogeny research within Tephritidae.

A novel mitochondrial genome fragmentation pattern in Liposcelis brunnea, the type species of the genus Liposcelis (Psocodea: Liposcelididae).

Booklice in the genus Liposcelis (Psocodea: Liposcelididae) are essential storage pests worldwide. Fragmented mt genomes have been identified in the Liposcelis species together with the typical mitochondrial (mt) genome, which is a single circular chromosome with 37 genes. Gene rearrangement, pseudogenes, and repeat regions (RRs) are very common among fragmented mt genomes. We sequenced the mt genome of the booklouse L. brunnea, the type species of the genus Liposcelis. We identified 37 genes in the mt genome of L. brunnea, which was fragmented into three chromosomes. The chromosomes I, II, III were 7.3 kb, 5.5 kb, and 5.3 kb in size with 9, 19, and 15 genes, respectively. In addition, 16 pseudogenes and four repeat regions were present in three chromosomes. Gene rearrangement in the mt genome of L. brunnea was obvious compared to that in other mt genomes in the genus Liposcelis. We found a possible correlation among mt genome rearrangement, the morphological classification standard, and phylogenetic relationships. In summary, a three-chromosome mt genome in an insect was identified for the first time, which may aid in understanding mt genome fragmentation, gene rearrangement, and evolution.

The first complete mitochondrial genome of the Japanese beetle Popillia japonica (Coleoptera: Scarabaeidae) and its phylogenetic implications for the superfamily Scarabaeoidea.

Popillia japonica is a harmful pest with a wide range of hosts, presenting particular dangers to golf courses, lawns, and pastures. Very limited molecular data for Po. japonica are available in GenBank, including only some partial nuclear gene or mitochondrial gene sequences, and acquiring more molecular information is urgent for studying the diagnosis of infestation, phylogeny, and evolution of this beetle. Herein, we characterize the complete mitochondrial genome of Po. japonica using next-generation sequencing and describe its structural features. The circular mitochondrial genome of Po. japonica is 16,541 bp in size, containing thirteen protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), twenty-two transfer RNA genes (tRNAs), and a control region. The base composition of the whole mitochondrial genome of Po. japonica is 39.00%, 9.50%, 14.80%, and 36.70% for A, G, C, and T, respectively, demonstrating high A + T content (75.70%). Phylogenetic relationships of the superfamily Scarabaeoidea show that Po. japonica and Protaetia brevitarsis form in a clade that is a sister group to Rhopaea magnicornis and Polyphylla laticollis from Melolonthinae. Cheirotonus jansoni from Melolonthinae is a sister group with Po. japonica, Protaetia brevitarsis, Rhopaea magnicornis and Polyphylla laticollis, indicating that Melolonthinae is a polyphyletic group. This is the first report of a complete mitochondrial genome of Po. japonica and it will contribute to further studies of infestation diagnosis, phylogeny, and evolution of Scarabaeoidea.

The first complete mitochondrial genome of Bactrocera tsuneonis (Miyake) (Diptera: Tephritidae) by next-generation sequencing and its phylogenetic implications.

Bactrocera tsuneonis (Miyake), generally known as the Japanese orange fly, is considered to be a major pest of commercial citrus crops. It has a limited distribution in China, Japan and Vietnam, but it has the potential to invade areas outside of Asia. More genetic information of B. tsuneonis should be obtained in order to develop effective methodologies for rapid and accurate molecular identification due to the difficulty of distinguishing it from Bactrocera minax based on morphological features. We report here the whole mitochondrial genome of B. tsuneonis sequenced by next-generation sequencing. This mitogenome sequence had a total length of 15,865 bp, a typical circular molecule comprising 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a non-coding region (A + T-rich control region). The structure and organization of the molecule were typical and similar compared with the published homologous sequences of other fruit flies in Tephritidae. The phylogenetic analyses based on the mitochondrial genome data presented a close genetic relationship between B. tsuneonis and B. minax. This is the first report of the complete mitochondrial genome of B. tsuneonis, and it can be used in further studies of species diagnosis, evolutionary biology, prevention and control.

The mitochondrial genomes of the barklice, Lepinotus reticulatus and Dorypteryx domestica (Psocodea: Trogiomorpha): Insight into phylogeny of the order Psocodea.

The order Psocodea which has incorporated the two former orders Psocoptera (barklice and booklice) and Phthiraptera (parasitic lice) attracts much attention for its unusual mitochondrial (mt) genome rearrangements. Available phylogenetic analysis for Psocodea is subjected to partial taxa and a complete one is needed. To further explore the genome rearrangement and phylogeny in Psocodea, we sequenced the mt genomes of two barklice, Lepinotus reticulatus (collected from China) and Dorypteryx domestica (collected from Czech Republic). Both of newly sequenced barklice had typical one-chromosome mt genomes and the same mt gene arrangement with the reported Lepidopsocidae sp. The mt genomes of L. reticulatus and D. domestica contained 37 genes typical of bilateral animals. In contrast with the recent report mt genome of D. domestica, our strain was found with many single nucleotide polymorphisms in intra-specific difference. Phylogenetic relationships were inferred from all available mt genomes of Psocodea data using Maximum Likelihood and Bayesian methods. The mt genome of L. reticulatus is the first representative with complete sequences of the family Trogiidae and our D. domestica data enriched the family Psyllipsocidae, which will contribute to the further study of mt gene rearrangement and phylogeny of Psocodea.

The Highly Divergent Mitochondrial Genomes Indicate That the Booklouse, Liposcelis bostrychophila (Psocoptera: Liposcelididae) Is a Cryptic Species.

The booklouse, Liposcelis bostrychophila is an important storage pest worldwide. The mitochondrial (mt) genome of an asexual strain (Beibei, China) of the L. bostrychophila comprises two chromosomes; each chromosome contains approximate half of the 37 genes typically found in bilateral animals. The mt genomes of two sexual strains of L. bostrychophila, however, comprise five and seven chromosomes, respectively; each chromosome contains one to six genes. To understand mt genome evolution in L. bostrychophila, and whether L. bostrychophila is a cryptic species, we sequenced the mt genomes of six strains of asexual L. bostrychophila collected from different locations in China, Croatia, and the United States. The mt genomes of all six asexual strains of L. bostrychophila have two chromosomes. Phylogenetic analysis of mt genome sequences divided nine strains of L. bostrychophila into four groups. Each group has a distinct mt genome organization and substantial sequence divergence (48.7-87.4%) from other groups. Furthermore, the seven asexual strains of L. bostrychophila, including the published Beibei strain, are more closely related to two other species of booklice, L. paeta and L. sculptilimacula, than to the sexual strains of L. bostrychophila Our results revealed highly divergent mt genomes in the booklouse, L. bostrychophila, and indicate that L. bostrychophila is a cryptic species.

The mitochondrial genome of the wolfberry fruit fly, Neoceratitis asiatica (Becker) (Diptera: Tephritidae) and the phylogeny of Neoceratitis Hendel genus.

Neoceratitis asiatica (Becker) (Diptera: Tephritidae) is one of the most important fruit pestsof wolfberry which is a traditional Chinese medicinal herb. We characterized the complete mitochondrial genome of N. asiatica and described its organization in this study. This mitogenome had a total length of 15,481 bp, consisting of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a non-coding region (A + T-rich control region). The overall base composition of N. asiatica in descending order was 40.6% A, 8.5% G, 38.4% T and 12.6% C. The phylogenetic relationships shows that Ceratitis capitata and N. asiatica may be sister taxa. This is the first report of the complete mitochondrial genome of a member of the Neoceratitis Genus and the complete mitochondrial genome sequence may provide useful information for phylogenetic analysis and studies between the genera Ceratitis and Neoceratitis.

Molecular Identification of ten species of stored-product psocids through microarray method based on ITS2 rDNA.

Stored-product psocids (Psocoptera: Liposcelididae) are cosmopolitan storage pests that can damage stored products and cause serious economic loss. However, because of the body size (~1 mm) of eggs, nymphs, and adults, morphological identification of most stored-product psocids is difficult and hampers effective identification. In this study, 10 economically important stored-product Liposcelis spp. psocids (Liposcelis brunnea, L. entomophila, L. decolor, L. pearmani, L. rufa, L.mendax, L. bostrychophila, L. corrodens, L. paeta, and L. tricolor) were collected from 25 geographic locations in 3 countries (China, Czech Republic, and the United States). Ten species-specific probes for identifying these 10 psocid species were designed based on ITS2 sequences. The microarray method and reaction system were optimized. Specificity of each of the ten probes was tested, and all probes were found suitable for use in identification of the respective10 Liposcelis spp. psocids at 66 °C. This method was also used to identify an unknown psocid species collected in Taian, China. This work has contributed to the development of a molecular identification method for stored-product psocids, and can provide technical support not only to facilitate identification of intercepted samples in relation to plant quarantine, but also for use in insect pest monitoring.